<!DOCTYPE html>
<html>
  <head>
    <meta content="text/html;charset=utf-8" http-equiv="Content-Type">
    <meta content="utf-8" http-equiv="encoding">
    <script src="https://cdnjs.cloudflare.com/ajax/libs/svg.js/2.6.3/svg.min.js"></script>
    <script src="../dist/jspsych.js"></script>
    <script src="../dist/plugin-virtual-chinrest.js"></script>
    <script src="../dist/plugin-html-keyboard-response.js"></script>
    <link rel="stylesheet" href="../dist/jspsych.css"></link>
  </head>
  <script>

    var jsPsych = initJsPsych({
      on_finish: function() {
        jsPsych.data.displayData();
      }
    });

    // two blindspot estimates
    // measure px2mm, px2deg, viewing distance 
    // resize to cm (50 pixels per unit)
    // note: you may still choose to estimate viewing distance even if resizing to cm or inches
    let cm_resize = {
      type: jsPsychVirtualChinrest,
      blindspot_reps: 2, 
      resize_units: "cm",
      pixels_per_unit: 50,
      item_path: 'img/card.png',
    };

    // one blindspot estimate
    // measure px2mm, viewing distance and px2deg
    // resize to degrees of visual angle (50 pixels per unit)
    // don't report viewing distance to subject
    let deg_resize = {
      type: jsPsychVirtualChinrest,
      blindspot_reps: 1,
      resize_units: "deg",
      pixels_per_unit: 50,
      viewing_distance_report: 'none'
    };

    // one blindspot estimate
    // estimate viewing distance but do not resize
    // note: pixels_per_unit will be ignored
    let no_resize = {
      type: jsPsychVirtualChinrest,
      blindspot_reps: 3,
      resize_units: "none",
      pixels_per_unit: 50 
    };

    // resizing to degrees with no blindspot measurment (blindspot_reps: 0) is not possible
    // this trial will throw an error
    let error_trial = {
      type: jsPsychVirtualChinrest,
      blindspot_reps: 0, 
      resize_units: "deg",
      pixels_per_unit: 50
    };

    let validation_trial = {
      type: jsPsychHtmlKeyboardResponse,
      stimulus: '<div style="margin: auto; width: 200px; height: 200px; background-color: black;"></div>',
      prompt: '<p>The stimulus above should be 4cm x 4cm if resizing worked properly.</p>'
    };

    jsPsych.run([cm_resize, validation_trial]); // deg_resize, no_resize, error_trial

  </script>
</html>
